1. Field of the Invention
The present invention relates to a vehicular mirror device in which an axially movable drive shaft is coupled to a mirror holder swingably supported by a fulcrum disposed on a straight line perpendicular to the axis of the drive shaft, one end part of an operating shaft disposed on the straight line on a side opposite to the drive shaft relative to the fulcrum is swivelably coupled to the mirror holder, and a detection rod of a sensor fixed to a fixed support member is coupled to the operating shaft, which is slidably inserted into a guide hole provided in the support member so as to extend parallel to the drive shaft, so that it detects a swing angle of the mirror holder according to an axial position of the operating shaft.
2. Description of the Related Art
U.S. Pat. No. 6,094,027 discloses a vehicular mirror device in which a detection rod of a sensor fixed to a support member is coupled to an operating shaft having one end mounted on a mirror holder, and a swing angle of the mirror holder is detected by detecting an axial position of the operating shaft.
In the arrangement disclosed in U.S. Pat. No. 6,094,027, the sensor is fixedly disposed in an attitude at an inclination of 45 degrees relative to a straight line linking a part of a drive shaft that couples the drive shaft to the mirror holder, the fulcrum of the mirror holder, and a part of the operating shaft that couples the operating shaft to the mirror holder. The part of the operating shaft that couples the operating shaft to the mirror holder moves in a direction along the above-mentioned straight line by an amount allowed in a gap between an inner face of a guide hole and an outer face of the operating shaft in response to swing of the mirror holder, and the operating shaft swings within the guide hole by this amount. Therefore, in this conventional structure in which the sensor is fixedly disposed in an attitude at an inclination of 45 degrees relative to the straight line, a force is exerted on the detection rod of the sensor from a direction at an inclination of 45 degrees, so that the position of the detection rod becomes uncertain, and consequently the accuracy of detection of the axial position of the operating shaft by the sensor becomes unstable, thus resulting in a deteriorated accuracy of the sensor in detecting the swing angle of the mirror holder.